Late Complications of Head and Neck Radiation
Intraoral electrical stimulation devices delivering a low-intensity electrical current to the oral mucosa-thus stimulating salivary gland secretion by innervating afferent neurons of the salivary reflex and efferent neurons (e.g., the lingual nerve)-is under development and has been tested, with promising initial results in the palliation of xerostomia.; Special considerations appear to be indicated when electrostimulation devices are used in head and neck radiation patients.[Level of evidence: I] Further studies are needed.
The risk of dental caries increases secondary to a number of factors, including shifts to a cariogenic flora, reduced concentrations of salivary antimicrobial proteins, and loss of mineralizing components. (Refer to the Conditions Affected By Both Chemotherapy and Head/Neck Radiation section for more information.) As reported in a systematic review, the overall count of decayed, missing, or filled teeth (DMFT) in patients who were post-antineoplastic therapy was 9.19 (standard deviation [SD], 7.98; n = 457). The DMFT for patients who were post-radiation therapy was 17.01 (SD, 9.14; n = 157), which was much higher than that in patients who were postchemotherapy (DMFT, 4.5).
Treatment strategies must be directed to each component of the caries process. Optimal oral hygiene must be maintained. Xerostomia should be managed whenever possible via salivary substitutes or replacements. Caries resistance can be enhanced with the use of topical fluorides and/or remineralizing agents. Efficacy of topical products may be enhanced by increased contact time on the teeth by application using vinyl carriers. Patients unable to effectively comply with use of fluoride trays should be instructed to use brush-on gels and rinses.
Increased colonization with Streptococcus mutans and Lactobacillus species increases caries risk. Culture data can be useful in defining level of risk in relation to colonization patterns. Topical fluorides or chlorhexidine rinses may lead to reduced levels of S. mutans but not Lactobacilli. Because of adverse drug interactions, fluoride and chlorhexidine dosing should be separated by several hours.
Remineralizing agents, which are high in calcium phosphate and fluoride, have demonstrated salutary in vitro and clinical effects. The intervention may be enhanced by delivering the drug via customized vinyl carriers. This approach extends the contact time of active drug with tooth structure, which leads to increased uptake into enamel.
A systematic review of managing dental caries in post-radiation therapy patients produced the following conclusions:[27,28]
- Fluoride: The use of fluoride products reduces caries activity in patients who are post-radiation therapy. The type of fluoride gel or fluoride delivery system used did not significantly influence caries activity.
- Chlorhexidine: The use of chlorhexidine rinse reduces plaque scores and oral streptococcus mutans scores. This reduction was not seen with lactobacillus counts.
- Dental restorative materials: There is evidence suggesting that conventional glass ionomer restorations performed more poorly than did resin-modified glass ionomer, composite resin, and amalgam restorations in patients who had been treated with radiation therapy.